Medical Device

This application is entitled to and claims the benefit of Japanese Patent Application No. 2024-056573, filed on Mar. 29, 2024, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety.

The technology of the present disclosure relates to medical devices, such as devices for treating sleep apnea syndrome.

Sleep apnea syndrome (SAS) is a condition with a state where breathing stops (apnea) and a state where breathing becomes weak (hypopnea) repeating intermittently during sleep. Patients suffering from sleep apnea syndrome often do not get enough sleep, leading to daytime drowsiness, decreased concentration, an increased risk of serious accidents due to drowsiness while driving, and the like. Most patients suffering from sleep apnea syndrome exhibit symptoms of obstructive sleep apnea (OSA). Obstructive sleep apnea occurs when muscle tone decreases during inhalation in sleep, causing the upper airway to narrow.

For patients with such obstructive sleep apnea, continuous positive airway pressure (CPAP) therapy may be administered. CPAP therapy is a treatment method that prevents apnea during sleep by continuously supplying air to an airway of a patient to keep the airway open.

Traditionally, devices that perform CPAP therapy are referred to as sleep apnea syndrome treatment devices or CPAP devices. Herein, devices that perform CPAP therapy will be referred to as CPAP devices. CPAP devices are described in, for example, PTLbelow.

A CPAP device includes an air blower, a flow sensor, and a controller, and is configured to generate an airflow suitable for expanding an airway of a patient. Some CPAP devices include a water tank to humidify the airflow to be sent to a patient, preventing the airway of the patient from drying out.

Such a CPAP apparatus is described in, for example, Japanese Patent Application Laid-Open No. 2023-071739.

When a CPAP device is used for sleep, the lights in the room are usually turned off, making the room dark. Therefore, since the room is dark before sleep and upon waking, there is a possibility that the patient may accidentally bump into the CPAP device and cause it to fall over. Furthermore, the CPAP device may fall over due to, for example, the patient turning over in their sleep.

However, it cannot be said that sufficient consideration has been given to measures against these issues, and therefore, such measures have been insufficient in terms of safety and reliability.

The present disclosure has been made in consideration of the above circumstances and provides a medical device with improved safety and reliability.

One aspect of the medical device of the present disclosure includes:

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

As illustrated in, CPAP deviceis connected via tubeto maskworn on the face of patientsuffering from sleep apnea syndrome, and delivers an airflow with a positive pressure to the upper airway of patientto expand the upper airway. In the present embodiment, CPAP devicerepresents the main body of the CPAP device, and the CPAP device is configured to include CPAP deviceas the CPAP device main body, mask, and tube.

are perspective views of CPAP devicefrom diagonally above. Here, the +Z direction in the drawing indicates the upward direction of CPAP device, and the −Z direction indicates the downward direction of CPAP device. In addition, the +Y direction indicates the forward direction of CPAP device, and the −Y direction indicates the backward direction of CPAP device. Furthermore, the +X direction indicates the left direction of CPAP device, and the −X direction indicates the left direction of CPAP device.

As can be seen from, tube connector, to which tube() is connected, protrudes from the front side surface of housing caseof CPAP device. In addition, operation panelis provided on the upper part of housing case. Operation panelis provided with operation inputincluding operation buttons, and display

As can be seen from, intake portand power connectorare provided on the rear side surface of housing case. Power connectorreceives an AC power supply via a power cable. In addition, water tankis detachably attached to the side surface of housing case.

is an exploded perspective view of CPAP deviceaccording to the present embodiment.

CPAP devicemainly includes housing case, circuit board, flow path case, and base.

Housing casehas a rectangular cylindrical shape and houses circuit board, flow path case, and the like by being coupled from above to base.

Circuit boardis provided with a central processing unit (CPU), various driver circuits, and the like. In addition, in the present embodiment, circuit boardis provided with acceleration sensor.

Flow path caseis configured by fitting a lower caseand an upper casetogether. Inside flow path case, bloweras the first blower is disposed. Flow path, through which the wind generated by blowerpasses, is formed inside flow path case.

A detachable water tankis disposed on base. Air inletand air outletare formed on lidof water tank. Air inletcommunicates with flow pathlocated inside flow path case. Air outletcommunicates with tube connector.

As can be seen from the schematic diagram in, an airflow (indicated by arrows in the drawing) generated by blowerthus passes through flow pathof flow path case(), enters water tankthrough air inletis discharged from water tankthrough air outletand is supplied to the patient via tube connector.

Heateris provided on the lower surface side of water tank. The water in water tankis heated by heaterto create a high humidity state inside water tank. Therefore, the airflow to be supplied to the patient is humidified inside water tank. This reduces the drying of the airway of patientby the airflow.

In addition, baseis provided with AC/DC converter. AC/DC converterreceives AC power from the outside through a power cord (not illustrated) connected to power connector(), converts the power to DC power, and supplies the DC power obtained by the conversion to circuit boardand the like.

A plurality of circuit components constituting AC/DC converterare covered from the bottom and both left and right sides by sheet metal memberthat has a U-shaped cross section taken along the XZ plane. Sheet metal memberextends in the Y direction. At one end of sheet metal member, fanis provided as a second air blower to cool AC/DC converter. Fanis provided at a position to face AC/DC converter.

Thus, AC/DC converteris efficiently cooled by the wind from fan, flowing inside sheet metal memberin the extending direction of sheet metal member. In addition, the electromagnetic noise generated by AC/DC converteris blocked by sheet metal member.

is a block diagram for explaining the configuration of CPAP device.

In addition to blower, filter, temperature sensor, humidity sensor, flow sensor, and pressure sensorare provided at flow pathof CPAP device. In addition, temperature sensoris attached to heaterthat heats water tank, and a weight sensoris attached to water tank.

Circuit boardis provided with acceleration sensor, controller, heating controller, respiratory waveform analyzer, communicator, storage, and the like. In other words, circuit boardis equipped with circuit components to realize the functions of acceleration sensor, controller, heating controller, respiratory waveform analyzer, communicator, and storage.

Controller, heating controller, and respiratory waveform analyzerinclude a central processing unit (CPU), read only memory (ROM), random access memory (RAM), and the like. The CPU reads out a program corresponding to the processing content from the ROM and deploys the program in the RAM, and cooperates with the loaded program to realize the functions of controller, heating controller, and respiratory waveform analyzer. All or part of controller, heating controller, and respiratory waveform analyzermay be formed from hardwired circuits such as an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA).

When bloweroperates, external air enters flow paththrough intake portand filter. The temperature and humidity of the air in flow pathare measured by temperature sensorand humidity sensor, and the measured temperature and humidity are sent to heating controller. Furthermore, heating controllerreceives the heating set value and humidification set value (e.g., target temperature and target humidity) from operation inputalong with the temperature information of heaterfrom temperature sensor.

Heating controllercontrols heaterbased on the temperature and humidity information measured by temperature sensorand humidity sensor, the heating set value and humidification set value from operation inputset by the user, and the temperature information of heaterfrom temperature sensor. For example, heating controllercontrols heaterso that the temperature and humidity of the airflow to be supplied to patientapproach the heating set value and humidification set value.

In addition, heating controllerreceives temperature information from temperature sensorprovided at tube. Heating controllercontrols heaterprovided at tubebased on this temperature information to prevent condensation within tube.

Flow sensoris a differential pressure sensor that measures the respiratory flow of patientand sends the measurement result to respiratory waveform analyzer. Respiratory waveform analyzerperforms analyze to acquire the respiratory waveform of patientbased on the respiratory flow and sends the acquired respiratory waveform as respiratory information to controllerand communicator.

The information on the pressure in flow pathmeasured by pressure sensoris sent to controller. In addition, controllerreceives pressure setting information (e.g., target pressure) from operation inputControllercontrols the rotation of blowerbased on the pressure information measured by pressure sensor, the respiratory information from respiratory waveform analyzer, and the pressure setting information from operation inputset by the user, thereby controlling the pressure of the airflow supplied to patient.

The acceleration information (detected value) measured by acceleration sensoris sent to controller, communicator, and storage.

Controllercontrols the operation of CPAP devicebased on the acceleration information. Controllerperforms determinations regarding CPAP device, such as drop, fall, impact, and vibration, based on the acceleration information, and when controllerdetermines that CPAP devicehas dropped, fallen, been impacted, or vibrated, controllerstops the operation of all or part of CPAP device.

Communicatorcommunicates with external system. For example, the respiratory information obtained by respiratory waveform analyzeris transmitted to external systemvia communicator. This allows medical personnel at a distance from CPAP deviceto know that patientis experiencing apnea.

In addition, the acceleration obtained by acceleration sensor, the determination results regarding the drop, fall, impact, and vibration obtained by controller, and the operation stop information performed by controllerare transmitted to external systemvia communicator. This allows the acceleration that occurred in CPAP device, drop, fall, impact, vibration, and operation stop to be known at external system. As a result, when external systemis a system server of a management company, such information can be utilized for maintenance work of CPAP device.

Next, a processing example using acceleration sensorin the present embodiment will be specifically described.

is a flowchart illustrating the control flow using acceleration sensoraccording to the present embodiment. In step S, controllerstarts the operation of CPAP deviceby controlling the drive of blower, heater, and the like. After starting the operation, controllercontinuously or periodically measures the amount of water (i.e., water amount) in water tankand stores the information.

In the subsequent step S, controllerdetermines whether a drop, fall, vibration, or impact of CPAP deviceis detected. Specifically, controllerdetermines whether CPAP devicehas dropped, fallen, vibrated at a predetermined value or more, or received an impact at a predetermined value or more, based on the acceleration information from acceleration sensor.

When a positive result is obtained in step S(step S; YES), controllerproceeds to step S. In step S, controllerdetermines whether the amount of water in water tankis equal to or more than a threshold. In the example of the present embodiment, controllerestimates the amount of water in water tankbased on the measurement results of the weight sensorand performs threshold determination.

When a positive result is obtained in step S(step S; YES), controllerproceeds to step S. In step S, controllerdetermines that CPAP deviceis in an emergency state and stops blowerand heatersand.

By performing the control as illustrated in, even when CPAP devicedrops, falls over, or sways violently, and water overflowing from water tankenters tube, the water is not pumped to patientby the blower, thus the water overflowing from the water tankis prevented from being mistakenly sent to the airway of patient. In addition, when CPAP devicedrops, falls over, or sways violently, heatersandare stopped, which prevents damage to heatersandand burns to the user that would be caused by overheating of the heatersanddue to empty heating or the like.

It is also possible to proceed to step Swithout performing the processing of step Swhen a positive result is obtained in step S.

This configuration allows for the realization of CPAP devicewith improved safety and reliability.

In countries like Japan, where it is customary to sleep on the floor, CPAP deviceis often placed on the floor, posing a risk that a patient or family members may accidentally kick CPAP device, causing it to fall over. There is also a risk that CPAP devicemay fall over due to, for example, tossing and turning in sleep. On the other hand, in countries like those in Europe and America, where it is customary to sleep in beds, CPAP deviceis often placed higher than the floor, posing a risk of CPAP devicebeing dropped. Furthermore, in countries with many earthquakes, there is a risk that CPAP devicemay drop, fall over, or sway violently due to an earthquake.

In such cases, CPAP deviceof the present embodiment can prevent water from entering tube, thereby preventing clogging of tubeby water. Even when water enters tube, the water can be prevented from being sent toward mask. Furthermore, overheating of heatersandcan be prevented, thus avoiding damage to heatersandand burns to the user.